Dear Teachers

could you please explain to me the following words and idioms which i came across while reasding in the Cobuild Dictionary for Idioms

They are : at stake, on a high note as you can see them in the following
exampels :


1- But for the presedent there is more at streets - his whole political future could go up in smoke

2- Terry Wagon is determided to *beep* a snook at the critics and go out on a high note.

thanks